secondo/Algebras/DBService2/DBServiceClient.hpp

/*

1.1 \textit{DBServiceClient}

The \textit{DBServiceClient} is the central component of the system which
shall be equipped with fault-tolerant query execution capabilities. The
\textit{DBServiceClient} is the single point of entry for all operators
which need access to the \textit{DBService}.

----
This file is part of SECONDO.

Copyright (C) 2017,
Faculty of Mathematics and Computer Science,
Database Systems for New Applications.

SECONDO is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.

SECONDO is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with SECONDO; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
----

*/
#ifndef ALGEBRAS_DBSERVICE_DBSERVICECLIENT_HPP_
#define ALGEBRAS_DBSERVICE_DBSERVICECLIENT_HPP_

#include <string>
#include <vector>

#include <boost/shared_ptr.hpp>
#include "boost/filesystem.hpp"

#include "NList.h"

#include "Algebras/DBService2/CommunicationClient.hpp"
#include "Algebras/DBService2/LocationInfo.hpp"

namespace fs = boost::filesystem;

namespace DBService {

/*

1.1.1 Class Definition

*/

class DBServiceClient {
public:

/*


1.1.1.1 getInstance

Returns the DBServiceClient instance (singleton).

*/
    static DBServiceClient* getInstance();

/*
1.1.1.1 \textit{triggerReplication}

This function needs to be called if a relation shall be replicated.

*/
    bool triggerReplication(
            const std::string& databaseName,
            const std::string& relationName,
            const ListExpr relType,
            const bool async);


/*
1.1.1.1 triggerDerivation

*/
   bool triggerDerivation(
            const std::string& databaseName,
            const std::string& targetName,
            const std::string& relName,
            const std::string& fundef);


/*
1.1.1.1 \textit{retrieveReplicaAndGetFileName}

This function triggers the transfer of a file containing the replica of the
specified relation and returns the file name to the caller. The file name can
then be used to read a tuple stream from the file.

*/
   fs::path retrieveReplicaAndGetFileName(
            const std::string& databaseName,
            const std::string& relationName,
            const std::vector<std::string>& otherObjects,
            const std::string&
            functionAsNestedListString);

/*
1.1.1.1 \textit{deleteReplicas}

In case a relation is deleted locally, its replicas are also not longer needed.
This function triggers the deletion of the replicas as well as the removal of
all metadata related to this relation on the \textit{DBService} master node.

*/
    bool deleteReplicas(
            const std::string& databaseName,
            const std::string& relationName,
            const std::string& derivateName);

/*
1.1.1.1 ~pingDBService~

This function checks whether a connection to the ~DBService~ is possible.

*/
    bool pingDBService();

/*
1.1.1.1 ~getStreamType~

This function checks whether a relation exists in the ~DBService~ and provides
the corresponding tuple type if applicable.

*/
    bool getStreamType(
            const std::string& databaseName,
            const std::string& relationName,
            std::string& nestedListAsString);


/*
1.1.1.1 ~getDerivedType~

This function checks whether a derived object exists in the ~DBService~ and 
provides the type if applicable.

*/
   bool getDerivedType(
           const std::string& databaseName,
           const std::string& relationName,
           const std::string& derivedName,
           std::string& nestedListAsString);

/*
1.1.1.1 ~relationExists~

This function returns whether or not a relation exists in the ~DBService~.

*/
    bool relationExists(
            const std::string& databaseName,
            const std::string& relationName);


    bool allExists(
            const std::string& databaseName,
            const std::string& relationName,
            const std::vector<std::string>& derivates);

/*

1.1.1.1 ~addNode~

Request adding a node to the DBService.

*/

    bool addNode(
        const std::string& nodeHost,
        const int& nodePort,
        const std::string& pathToNodeConfig
    );

private:
/*
1.1.1.1 Constructor

*/
    DBServiceClient();

/*
1.1.1.1 Destructor

*/
    ~DBServiceClient();

/*
1.1.1.1 \textit{startReplicationServer}

This function is called by the constructor and starts a
\textit{ReplicationServer} on the current node.

*/
    void startReplicationServer();

/*
1.1.1.1 \textit{getReplicaLocation}

This function retrieves one of the replica locations of a relation from the
\textit{DBService} master. It is only called internally by the
\textit{retrieveReplicaAndGetFileName} function.

*/
    bool getReplicaLocation(
            const std::string& databaseName,
            const std::string& relationName,
            const std::vector<std::string>& otherObjects,
            std::string& host,
            std::string& transferPort,
            std::string& commPort);

/*

1.1.1.1 \textit{dbServiceHost}

Hostname of the node on which the \textit{DBService} master resides.

*/
    std::string dbServiceHost;

/*

1.1.1.1 \textit{dbServicePort}

Port of the \textit{CommunicationServer} on the \textit{DBService} master node.

*/
    std::string dbServicePort;

/*

1.1.1.1 \textit{\_instance}

Pointer to the \textit{DBServiceClient} instance (singleton).

*/
    static DBServiceClient* _instance;
};

} /* namespace DBService */

#endif /* ALGEBRAS_DBSERVICE_DBSERVICECONNECTOR_HPP_ */